/*
 * Copyright (C) 2010 Graham Allan
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.strath.cis.grallan.findbugs.adaptiveranking.population;

import edu.umd.cs.findbugs.BugInstance;

/**
 * A marker interface for a null population (Null Object Pattern), returning default values and
 * performing no-ops.
 * 
 * Importantly the adjustmentFactor() method for a NullPopulation should return 0, meaning it will
 * have no effect if included in additive formulas. <code>isValidAlert</code> should also be made to
 * return false.
 * 
 * This is useful when no sensible population can be created for a given {@link BugInstance}.
 * 
 * @author Graham Allan (grallan@cis.strath.ac.uk)
 */
public interface NullPopulation extends Population {

}
